/**
 * 宏定义
 */

#include <stdio.h>

#define max(x, y) ((x) > (y) ? (x) : (y))
#define dprint(expr) printf(#expr " = %g\n", expr)

int main(void) {
    double x, y;
    x = 10, y = 20;
    printf("%g", max(y, y));
    dprint(x/y);
    return 0;
}
